Various agent mode updates (#2094)

Author: jakebailey

.github/copilot-instructions.md

@@ -110,3 +110,4 @@ The TypeScript submodule serves as the reference implementation for behavior and
 
 - Do not add or change existing dependencies unless asked to.
 - Do not remove any debug assertions or panic calls. Existing assertions are never too strict or incorrect.
+- Do not use the `timeout` command when running tests or other commands, unless specifically debugging a hanging issue. Commands should be run directly without timeout wrappers in normal operation.

.github/workflows/copilot-setup-steps.yml

@@ -13,18 +13,24 @@ jobs:
       # If you want to clone the repository as part of your setup steps, for example to install dependencies, you'll need the `contents: read` permission. If you don't clone the repository in your setup steps, Copilot will do this for you automatically after the steps complete.
       contents: read
 
+    env:
+      MS_GOTOOLCHAIN_TELEMETRY_ENABLED: '0'
+
     # You can define any steps you want, and they will run before the agent starts.
     # If you do not check out your code, Copilot will do this for you.
     steps:
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
         with:
           submodules: true
       - uses: actions/setup-node@2028fbc5c25fe9cf00d9f06a71cc4710d4507903 # v6.0.0
+        with:
+          node-version: '>=22.16.0'
       - uses: dtolnay/rust-toolchain@fcf085fcb4b4b8f63f96906cd713eb52181b5ea4 # stable
       - uses: ./.github/actions/setup-go
         with:
           lint-cache: 'true'
       - run: npm i -g @playwright/[email protected]
+      - run: go install golang.org/x/tools/gopls@latest
       - run: npm ci
       # pull dprint caches before network access is blocked
       - run: npx hereby check:format || true